Can't say I'm too impressed at first try:

1. Slow to load
2. Interface not very intuitive, e.g. no player controls apparent (play/stop/pause etc)
3. Doesn't respond to any of the N800 buttons
4. Video playback performance seems much worse than mplayer standalone
5. Can't add a new folder under Settings - program just exits without error message

Ok, it's a 0.9 release, but this seems like pretty basic stuff for a media player.

Oh, and last but not least, on first reboot after installing Mediabox my N800 is now trashed and goes into a permanent loop on power-up. Removing the battery doesn't help. Any other suggestions before I re-install firmware?